I, for one, don't "see" principles of republican self government or political liberty in the pages of the Bible. But I understand that many ideas didn't just pop up out of nowhere during the Enlightenment but brewed for a long time previously in Christendom.
Republicanism traces to the Ancient noble pagan Greco-Roman tradition. Yet, Christianity was birthed there. (Well Christianity emerged in Rome after they transmogrified from a noble republic to an ignoble empire.)
But Mr. Fortenberry is not the first person to "see" republicanism in the pages of the Old Testament. The Whig propagandists -- indeed even Thomas Paine -- made similar arguments. Now, Paine, that Deist he who rejected every word of the Bible as special revelation, knew he was propagandizing.
But, perhaps caught up in the Whig-republican-revolutionary zeitgeist, seemingly sincere ministers preached something similar in their political sermons.
As Dr. Gregg Frazer reacts to them:
The sermons seem to depict God's role as something similar to Rousseau's legislator; He disinterestedly established the foundational law for the benefit of society, but did not live under it. In their version and consistent with democratic theory, God established it all [quoting Langdon's sermon] "for their happiness" rather than to achieve the fulfillment of a sovereignly determined plan. By their account, God submitted the laws to the people for their approval and acceptance (as per Rousseau's legislator).
-- Frazer, PhD thesis, pp. 393-94.